Rail pressure sensor
- Thread starter catman3126
- Start date
I was under the impression that too much pressure was messing up injectors at least on the LBZ. Stock injectors.
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Higher pressure then stock isn’t really recommended. I wouldn’t go over 180 MPA on a street truck that sees a decent amount of miles a year. For track use I don’t think the difference in wear will be all that noticeable.
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I'm not sure what the max pressure was on my built truck when it was together, but it was very high. I had two pumps running wide open, the pressure never dipped below 180mpa during a pass.
I hurt a pump during a pass one day and didn't know it, and the next pass I lost 10mph trap speed, from 132mph to 122mph. Looking at the logs the truck was still holding over 170mpa the whole pass. Fuel pressure alone caused that much of a power loss, calculator says over 200hp.
The issue with running huge pressure with lly injectors is cracking the bodies or blowing the check balls out. I never had an issue with that but like I said I did hurt a pump during a pressure spike.
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I hurt a pump during a pass one day and didn't know it, and the next pass I lost 10mph trap speed, from 132mph to 122mph. Looking at the logs the truck was still holding over 170mpa the whole pass. Fuel pressure alone caused that much of a power loss, calculator says over 200hp.
The issue with running huge pressure with lly injectors is cracking the bodies or blowing the check balls out. I never had an issue with that but like I said I did hurt a pump during a pressure spike.
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On our first engine, we ran one new stock pump with one modded pump and stock bodied 180% LLY injectors. I always ran the regulators wide open, made the pumps make as much pressure as possible. Only had the stock sensor though, so I have no way of knowing how high it actually got. It would stay pegged at it's max, 26107(180 MPA), for the entire run, never fluctuate. Never hurt anything at all like this for 2-3 seasons.
Did anyone ever figure this out? I definitely know there is power in rail pressure, With many different Duramax motors on the dyno.
I originally ran across the issue first with a buddies truck and 4600's iirc for sure S&S though injectors, we ended up limiting rail pressure down to 26,000 psi and it didn't have a issue. The truck currently has a 220mPa sensor in it and still doesn't like it. - LLY ECM truck.
My personal pulling truck, has 200% S&S injectors in it and it does the same thing just as everyone else has experienced as well. Not knocking S&S by any means because they have been of great help and I have had good luck with their injectors and making power... But I Did not have a issue with the DDP's I ran before that and other no name injectors as I have ran them wide open on the pumps and a factory LLY sensor. I now have a 220mpa sensor and limit it to about 28k and it is fine at that.
Everything I do with them I use higher reading sensors and try limiting no more than 28k but it would be really nice to do at least 30k . I have had Andrew say he thought it was a OS issue but I have tried many different ones and it has yet to solve it. Maybe a solution could be found if he has some time to play on a test stand.
I originally ran across the issue first with a buddies truck and 4600's iirc for sure S&S though injectors, we ended up limiting rail pressure down to 26,000 psi and it didn't have a issue. The truck currently has a 220mPa sensor in it and still doesn't like it. - LLY ECM truck.
My personal pulling truck, has 200% S&S injectors in it and it does the same thing just as everyone else has experienced as well. Not knocking S&S by any means because they have been of great help and I have had good luck with their injectors and making power... But I Did not have a issue with the DDP's I ran before that and other no name injectors as I have ran them wide open on the pumps and a factory LLY sensor. I now have a 220mpa sensor and limit it to about 28k and it is fine at that.
Everything I do with them I use higher reading sensors and try limiting no more than 28k but it would be really nice to do at least 30k . I have had Andrew say he thought it was a OS issue but I have tried many different ones and it has yet to solve it. Maybe a solution could be found if he has some time to play on a test stand.
We run s&s 4600's with a LLY ecm with the same result. I have to cap rp at 28xxx psi. Andrew told me the same thing he told you but also said he couldn't be of much help as he is not familiar with running OE ecm's.
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After talking to my tuner we are going to run the regs wide open on my dual 10mms and see what the 60s take while flying blind. Goal is to make 1k on 60s by cheating with pressure. Its a stretch but I know 2x 10mm will make a ton of fuel.
2x 10mm's will make 28k @ 2000us with 4600's(400+%) with a little ways to go yet on the regulators
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I just was getting at the fact that two 10's will make enough rail to shoot the moon.
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Touché hahahaha. I may pick up a 2700bar sensor from Exergy but part of me doesn’t want to know what the pressure is.
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Bumping this back up to fill in some data for people. I’ve done tons of testing on rail pressure the past two seasons. I recently took my lb7 to the track to test some different things on rail. Here is some of the data I collected. Truck weighs 6250lbs with me in it. Fueling is S&S 12mm and 100% S&S injectors.
1) 180MPa, 1950uS, ~23.5*, 11.0@123, ~550mA left
2) 190MPa, 1950uS, ~23.5*, 10.92@124, ~475mA left
3) 200MPa, 1950uS, ~23.5*, 10.82@125, ~400mA left
4) 200MPa, 2150uS, ~25.5*, 10.73@126, ~350mA left
- Those are real world results done at 3650ft, (6500ft DA), 83* temps. I know these aren’t 240MPa results but figured I’d share what the differences were.
** LML Rail Testing
We took a stock turbo, stock injector LML with a stock LBZ CP3 in place of the CP4.2 and tested rail pressure data on the dyno recently. (Numbers are close as the truck does run 12.9@105 at 7750lbs)
1) 200MPa, 1650uS, 19.5*, 563/1160, ~400mA left
2) 200MPa, 2050uS, 23.5*, 567/1155, 0mA (rail dropped to 27.5k)
3) 217MPa, 1650uS, 19.5*, 583/1192, ~150mA left
4) 217MPa, 1525uS, 18.5*, 561/1156, ~350mA left
-Will be adding a 2700bar sensor to this truck and a 10mm in place for the stock lbz pump and test rail pressure up to 36k. As you can see the 3rd pull was by far the most efficient pull we had. Will be hooking up a drive pressure gauge while we’re testing with the higher rail pressures. I’ll be collecting data and reporting back. Now since the sky is the limit with rail pressure on the lml platform and I’ve fully achieved full fuel(130mm3) up to the 4800-4900RPM ranges I feel like more lmls are going to be hitting the 10.99 list
1) 180MPa, 1950uS, ~23.5*, 11.0@123, ~550mA left
2) 190MPa, 1950uS, ~23.5*, 10.92@124, ~475mA left
3) 200MPa, 1950uS, ~23.5*, 10.82@125, ~400mA left
4) 200MPa, 2150uS, ~25.5*, 10.73@126, ~350mA left
- Those are real world results done at 3650ft, (6500ft DA), 83* temps. I know these aren’t 240MPa results but figured I’d share what the differences were.
** LML Rail Testing
We took a stock turbo, stock injector LML with a stock LBZ CP3 in place of the CP4.2 and tested rail pressure data on the dyno recently. (Numbers are close as the truck does run 12.9@105 at 7750lbs)
1) 200MPa, 1650uS, 19.5*, 563/1160, ~400mA left
2) 200MPa, 2050uS, 23.5*, 567/1155, 0mA (rail dropped to 27.5k)
3) 217MPa, 1650uS, 19.5*, 583/1192, ~150mA left
4) 217MPa, 1525uS, 18.5*, 561/1156, ~350mA left
-Will be adding a 2700bar sensor to this truck and a 10mm in place for the stock lbz pump and test rail pressure up to 36k. As you can see the 3rd pull was by far the most efficient pull we had. Will be hooking up a drive pressure gauge while we’re testing with the higher rail pressures. I’ll be collecting data and reporting back. Now since the sky is the limit with rail pressure on the lml platform and I’ve fully achieved full fuel(130mm3) up to the 4800-4900RPM ranges I feel like more lmls are going to be hitting the 10.99 list
